The act or ceremony of driving out demons from possessed persons, places, or things, or of protecting them from the influence of evil spirits. The practise is based on teachings of the Bible. Certain things are exorcised in blessing them, as holy water. In the prayer used in blessing holy water, God is besought to protect those who use it against the influence of the devil. Exorcism is part of the ceremonies of baptism. The Roman Ritual contains the ceremony of exorcism proper.